Organoaluminum and -gallium thiolates are prepared in high yield by the reaction of triorganoaluminum and -gallium derivatives with thiols. In this way, [Mes(2)Al(mu-SBz)](2) (Mes = 2,4,6-Me(3)C(6)H(2); Bz = CH2C6H5) (1), [Me(2)Al(mu-SSiPh(3))](2) (2), [Mes(2)Al(mu-SPh)](2) (3), {Me(2)Al[mu-S(2-t-BUC6H4)]}(3) (4), {Me(2)Al[mu-S(2-Me(3)Si)C6H4]}(3) (5), {Me(2)Al[mu-S(2-i-PrC6H4)]}(3) (6), {i-Bu(2)Al[mu-S(2,4,6-i-Pr3C6H2)]}(3) (7), {Me(2)Al[mu-S(2,6-Me(2)C(6)H3)]}(4) (8), and {Me(2)Ga[mu-S(2,6-Me(2)C(6)H(3))]}(4) (9) were prepared and crystallographically characterized. The dimethyl- and dimesitylaluminum thiolates 1-3 were determined to be dimeric with four-membered (AlS)(2) rings. The structure of 1 was determined in space group P2(1)/n (No. 14): a 10.666(4) Hi, b = 12.268(2) Angstrom, c = 17.793(3) Angstrom, beta = 106.94(2)degrees, Z = 4, R = 6.7%, and R(w) = 6.1%. The structures of 2 and 3 were determined in space group P (1) over bar (No. 2): a = 9.077(2) Angstrom, b = 13.847(3) Angstrom, c = 16.724(4) Angstrom, alpha = 101.08(2)degrees, beta = 95.34(2)degrees, gamma = 103.38(2)degrees, Z = 2(dimers), R = 5.2%, and R(w) = 5.1% for 2, and a = 11.068(5) Angstrom, b = 12.470(3) Angstrom, c = 17.654(5) Angstrom, alpha = 90.97(2)degrees, beta = 107.77(3)degrees, gamma = 112.23(3)degrees, Z = 4, R = 5.9%, and R(w) = 4.8% for 3. The dialkylaluminum thiolates, 4-7, were found to be trimeric in the solid state. The structure of 4 was determined in space group P2(1)/c (No. 14), a = 9.324(7) Angstrom, b = 18.632(5) Angstrom, c = 23.959(9) Angstrom, beta = 98.31(5)degrees, Z = 4 (trimers), R = 7.6%, and R(w) 5.2%; 5 in space group P (1) over bar (No. 2), a = 10.149(4) Angstrom, b = 14.427(5) Angstrom, c = 15.159(4) Angstrom, alpha = 88.19(3)degrees, beta = 89.39(3)degrees, gamma = 88.57(3)degrees, Z = 2 (trimers), R = 5.0%, and R(w) = 5.0%; 6 in space group P (1) over bar (No. 2), a = 12.538(5) Angstrom, b = 13.180(2) Angstrom, c = 13.873(2) Angstrom, alpha = 74.38(1)degrees, beta = 64.18(2)degrees, gamma = 69.44(2)degrees, Z = 2 (trimers), R = 5.2% and R(w) = 4.4%; and 7 in space group P2(1)/c (No. 14), a 13.935(2) Angstrom, b = 22.563(4) Angstrom, c = 25.044(4) Angstrom, beta = 101.44(1)degrees, Z = 4 (trimers), R = 12.5%, and R(w) = 14.2%. The sulfur atoms in 7 are in a planar environment. Compounds 8 and 9 are tetrameric with eight-membered (MS)(4) (M = Al, Ga) ring systems. They are isomorphous, and their structures were determined in space group P (1) over bar (No. 2). For 8 a = 8.555(1) Angstrom, b = 11.869(1) Angstrom, c = 12.688(1) Angstrom, alpha = 96.546(8)degrees, beta = 106.34(1)degrees gamma = 109.06(1)degrees, Z = 2, R = 5.0%, and R(w)= 5.2%, and for 9 a = 8.525(2) Angstrom, b = 11.805(3) Angstrom, c = 12.714(4) Angstrom alpha = 96.36(2)degrees, beta = 106.46(2)degrees, gamma = 108.90(2)degrees, Z = 2, R = 6.1%, and R(w) = 6.6%.